<!-- 纵向滚动 -->
<style>
  body::after {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 10px;
    background-color: #F44336;
    transform-origin: 0 50%;
    animation: grow-progress 1s linear;
    animation-timeline: scroll();
  }

  @keyframes grow-progress {
    from { transform: scaleX(0); }
    to { transform: scaleX(1); }
  }

  div{
    display: flex;
    align-items: center;
    justify-content: center;
    height: 300px;
    margin: 10px;
    background-color: beige;
    color: coral;
    font-size: 80px;
  }

  div:nth-child(odd){
    background-color:wheat
  }
</style>
<div>欢</div>
<div>迎</div>
<div>关</div>
<div>注</div>
<div>白</div>
<div>哥</div>
<div>学</div>
<div>前</div>
<div>端</div>
